L_(4～5)后路减压后不同融合模式的生物力学研究

Biomechanical evaluation of different lumbar fusion methods following laminotomy and discectomy of L_(4～5) in vitro

目的:评价侧后方融合(PLF)、经后路椎体间融合(PLIF)和360°融合(PLF+PLIF)对失稳腰椎的生物力学效果。方法:选择6具T12～S1人尸体腰椎标本,测试以下几种状态中L4～5、L3～4、L5～S1间隙在载荷下的轴向压缩(250N)和旋转(10Nm)运动:1完整脊柱;2L4～5全椎板减压+椎间盘切除(LAD);3PLF;4PLIF;5PLF+PLIF。结果:PLF、PLIF和PLF+PLIF处理后,融合节段位移值都明显低于正常,压缩减少(82%、67%、89%),旋转减少(36%、51%、73%);邻近节段运动均有增加,以PLF+PLIF和PLIF组较多,无显著统计学差异。结论:PLF、PLIF和PLF+PLIF都能达到稳定腰椎节段的作用。PLF是一种相对接近生理的融合方式。融合后邻近节段长期的异常运动积累可能是其退变的原因。

Objective：To evaluate the biomechanical effects of the posterolateral fusion（PLF）,posterior lumbar interbody fusion（PLIF） and PLF＋PLIF for spinal instability.Methods： Six human cadaveric T12～S1 specimens were tested in this following states： ①intact;②L4～5 after laminotomy and discectomy（LAD）;③PLF;④PLIF;⑤PLF＋PLIF.The ranges of motions（ROM） of L4～5 and the adjacent segments（L3～4 and L5～S1） were recorded when specimens were applied under the axial compression of 250N and axial rotation of 10Nm respectively.Results： The ROM of L4～5 after stand PLF,PLIF and PLF＋PLIF decreased 82%,67%,89% in compression and decreased 36%,51%,73% in rotation.The ROM of adjacent segments increased after stand PLF,PLIF and PLF＋PLIF,but it were insignificant in statistics,although the value of the PLF＋PLIF and PLIF groups were greater.Conclusions： The stabilities after stand PLF,PLIF and PLF＋PLIF are much better than intact lumbar spine.PLF is a relatively physiological fusion.The ROM of the adjacent segments increased and cycle hypermotility may result in the accelerated degradation.